Hydrorefining heavy oils using a pseudo-dry catalyst



Feb. 16, 1965 w. K. T. GLEIM HYDROREFINING HEAVY OILS USING A PSEUDO-DRYCATALYST Filed July 2, 1962 N 1/ EN r05; Will/am K. 71 6/6/11;

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ATTORNEYS United States Patent 3,169,918 HYDROREFINHWG HEAVY OILS USINGA PSEUDO-DRY CATALYST William K. T. Gleim, Island Lake, 111., assignorto Universal Gil Products Company, Des Plaines, 11].,

a corporation of Delaware Filed July 2, 1962, Ser. No. 206,919 Claims.(Cl. 208264) This invention relates to a process for upgrading heavyhydrocarbon stocks in the presence of hydrogen and a catalyst. Moreparticularly, the present invention is directed to an improved catalytichydrorefining process for effecting in a single operation thesubstantial removal of various types of impurities, as hereinafterdescribed, from crude oil, crude residua, and heavy distillates obtainedtherefrom.

Crude petroleum oil, topped crude, and other heavy hydrocarbon fractionsand/or distillates derived therefrom contain various nonmetallic andmetallic impurities. Among the nonmetallic impurities are nitrogen,sulfur and oxygen which exist in heteroatomic compounds and are oftenpresent in relatively large quantities. Nitrogen is undesirable becauseit rapidly poisons various catalysts which may be employed in theconversion of petroleum fractions; in particular, nitrogen must beremoved from all catalytic hydrocracking charge stocks. Nitrogen andsulfur are also objectionable because combustion of hydrocarbonaceousfuels containing these impurities releases nitrogen oxides and sulfuroxides which are noxious, corrosive and present a serious problem in thefield of air pollution. Sulfur, of course, is deleterious in motor fuelsbecause of odor, gum formation and decreased lead susceptibility.

Another class of undesirable constituents found in crude oil andresidual oils are asphaltenes which are non-distillable, oil-insoluble,high molecular weight coke precursors containing sulfur, nitrogen,oxygen and metals; they are colloidally dispersed in raw crude oil butwhen subjected to heat, as in vacuum distillation, the asphaltenesflocculate and polymerize thereby making their conversion to morevaluable oil-soluble products extremely diflicult; thus, in the heavybottoms from a reduced crude vacuum distillation column, the polymerizedasphaltenes are solid materials at ambient temperature. Such product isuseful only as road asphalt or, when out back with middle distillates,as low grade fuel and commands a price substantially below that of theraw crude oil itself.

The most common metallic contaminants are nickel and vanadium, althoughother metals including iron, cop per and zinc are often present. Thesemetals may occur as suspended metal oxides or sulfides or water-solublesalts which may be removed, at least in part, by filtration,water-washing, electric desalting, or other fairly simple physicalmeans; mainly, however, the metals occur as thermally stablemetallo-organic complexes such as metal porphyrins and derivativesthereof. Most of the metallo-organic complexes are linked with theasphaltenes and becomeconcentrated in residual fractions, but some ofthe remaining metallo-organic complexes are volatile, oil-soluble, andare therefore carried over in distillate fractions. Reducing theconcentration of the metalloorganic complexes is not easily achieved, atleast' to the extent that the crude oil or other heavy hydrocarboncharge stock may be made suitable for further processing. Even thoughthe concentration of these metallo-organic complexes may be relativelysmall in distillateoils, for example, often less than about 10 p.p.m. astheelemental metal,.subsequent processing techniques are often adverselyaffected thereby. For example, when a hydrocarbon charge stockcontaining metallo-organic compounds, such as metal porphyrins, inexcess of about 3,169,918 Patented Feb. 16, 1965 ice 3.0 p.p.m.calculated as the elemental metal, is subjected to hydrocracking orcatalytic cracking for the purpose of producing lower-boilingcomponents, the metals deposit upon the catalyst, the concentrationthereof increasing with time. Since vanadium and the iron group metalsfavor dehydrogenation activity, at cracking temperatures, the resultingcontaminated hydrocracking or cracking catalyst produces increasinglyexcessive amounts of coke, hydrogen and light hydrocarbon gases at theexpense of more valuable liquid product until eventually the catalystmust be subjected to elaborate regeneration techniques or be replacedwith fresh catalyst. The presence of excessive quantities ofmetallo-organic complexes adversely affects other processes includingcatalytic reforming, isomerization, hydrodealkylation, etc. Vanadiumitself is also objectionable in heavy fuel oils and residual solids usedas fuels because vanadium pentoxide formed during combustion is a strongacid at high temperature and will corrode the refractory lining, tubesupports and other internal hardware of a fired heater utilizing suchfuel.

The desirability of removing these impurities is obvious and well knownto workers in the art. Heretofore in the field of catalytichydrotreating, two principal approaches have been advanced: liquid phasehydrogenation and vapor phase hydrocracking. In the former type ofprocess, the oil is passed upwardly in liquid phase and in admixturewith hydrogen through a fixed bed or slurry of subdivided catalyst;although perhaps effective in removing oil-soluble metallo-organiccomplexes, it is relatively ineffective against oil-insolubleasphaltenes which are colloidally dispersed in the charge with theconsequence that the probability of effecting simultaneous contactbetween catalyst particle, asphaltene molecule and hydrogen is remote,at least at space velocities which are commercially attractive.Furthermore, since the hydrogenation zone is at elevated temperature,the retention of unconverted asphaltenes suspended in a free liquidphase oil for too long a time will result in their floccula tion whichmakes their conversion even more diflicult. Also, the efliciency ofhydrogen-to-oil contact obtainable by bubbling hydrogen through anextensive liquid body is relativelylow. Vapor phase hydrocracking iscarried out with either a fixed bed or expanded bed system attemperatures at substantially above 950 F.; while it obviates to someextent the drawbacks of liquid phase hydrogenation, it is not wellsuited totreating crude oil and residual oil because of high coke makeand resultant rapid deactivation of the catalyst which requires highcapacity catalyst regeneration equipment in order to implement theprocess on a continuous basis; furthermore, selective cracking of a wideboiling range charge stock is not easily obtained, and excessive amountsof light gases are produced at the expense of more valuableintermediates; also, when charging crude oil, a minimum limit on crackedgasoline production is unavoidable which is not always desirable wherethe refiner wishes to maximize production of middle and heavydistillates such as jet fuel, diesel oils, furnace oils and gas oils.

A principal object of the present invention is to hydrorefine a heavyoil under conditions which simulate a vapor phase operation but whichinvolve only minimal cracking which is selective toward asphaltenes,whereby to effect a very substantial reduction in the asphaltene contentof the charge stock through conversion thereof to oil-solublehydrocarbons.

Another object of the present invention is to substantially eliminatemetallic contaminants present in a heavy hydrocarbon charge stock.

Another object of this invention is to lower materially theconcentration of non-metallic impurities, e.g., nitrogen, sulfur andoxygen, present in a heavy oil whereby to eliminate or reduce the costof whatever subsequent distillate treating facilities may be required.

A further object of this invention is to provide a process for upgradingheavy oils under extremely mild hydrocracking conditions which maximizemiddle and heavy distillate production. V p

The processof the present invention can be characterized as a mixedphase combinationhydrorefining-stripping operation employing a fluidbedof pseudo-dry hydrogenation catalyst. It has beenfound that ahydrogenation catalyst comprising a porous, refractory inorganic oxidecarrier having a Well developed pore structure has the ability to sorbinto itspore 'structure a substantial quantity, e.g.,.up to about 50% byweight, of high-boiling hydrocarbons while yet appearing ostensibly dryand freeflowing. Such non-agglomerated oil-bearing catalyst isdesignatedherein as a pseudo-dry catalyst; representative compositionsand physicalcharacteristics of suitable catalytic composites are setforth more fully hereinbelow. It has further been found that convertedasphaltenes that is,asphaltenes"which have been hydrorefined under mild.

hydrogenative cracldngconditions. to yield oil-soluble high-boilinghydrocarbons, comprise an excellent'solvent for untreated asphalteneswhich arethemselves pentaneinsoluble and are colloidally dispersed in acrude -oil charge orjagglomeratively dispersed in a topped crude oilcharge. The untreated asphaltenes are muchmore readily converted tooil-soluble product when initially dissolved in such solvent than whendirectly treated in a dis persed phase suspended in liquid carrier. Theasphaltene solvent is sorbed into the pseudo-dry hydrogenation catalystparticlesand is preferentially retained thereby, as against lowerboiling portions of the hydrotreatedcharge stock, when said particlesare subjected to contact with a gaseous stripping medium. The instantinvention utilizes the foregoing properties to efiect in a singlyhydrotreating zone the substantial removal of asphaltenes, metals,nitrogen, oxygen and/or sulfur from heavy oils containing same.

. A broad embodiment of the present invention relates to a process forhydrorefining a heavy hydrocarbon oil which comprises'maintaining inahydrorefining zone under hydrorefining conditionsapseudo-dry fluidizedbed of absorptive hydrogenation catalyst particles, partially vaporizingsaid heavy oil by preheating it in the absence of catalystto atemperature below that at which any sub stantial thermal crackingthereof can occur, introducing the partiallyvaporized oil into saidhydrorefining zone and contacting it inthe presence of hydrogenwith'said catalyst particles, sorbing unvaporized oil into said.catalyst particles to avoid any substantial accumulation of free liquidphase oil within the hydrorefining zone, flowing a hydrogen-containinggas upwardly through said hydrorefining zone and therewith strippinghydrorefined oil from the, catalyst particles, withdrawing from saidhydro- 1 refining zone vaporous eiiluent and recovering therefromahydrorefined product of improved purity.

Another embodiment of the present invention is directed to a process forhydrorefininga heavy hydrocarbon oil containing asphaltenes whichcomprises partially vaporizing the oil by preheating it to a temperaturebelow that at which any substantial thermal cracking thereof can occur;maintaining in.a hydrorefiningzone under hydr-orefining conditions apseudo-dry fluidized bed of absorptive hydrogenation catalyst particleshaving sorbed therein a liquid-phaseasphaltene :solvent comprisinghydrorefined asphaltenes; introducingsaid partially vaporized oil intosaid hydrorefining zone 'a'nd contacting it in the presence of hydrogenwith said solvent-bearing catrefining zone, and dissolvingin theparticle-held solvent the asphaltenes.containedin. the embed oil;converting said dissolved asphaltenes into additional'asphaltene' sol-'4 vent; flowing a hydrogen-containing gas upwardly through saidhydrorefining zone and therewith stripping hydrorefined oil from thecatalyst particles but leaving sorbed therein a portion of saidasphaltene solvent; contacting the resulting" stripped solvent-bearingcatalyst particles with additional incoming heavy oil; and withdrawingfrom said hydrorefining zone vaporous efiiuent and recovering therefromhydrorefined oil of reduced asphaltene content.

.. ing the partially vaporized oil into said hydrorefining zone at arate of about 0.25-20 pounds of total oil charged per pound of catalystpresent in. said zone per hour and therein contacting said partiallyvaporized oil in the presence of hydrogen with said catalyst particles;sorbing unvaporized oil into said catalystparticles to avoid any substantial accumulation of free liquid phase oil'within the hydrorefiningzoneg flowi'ng a heated hydrogen-containing gas upwardly through saidhydrorefining zone at a rate of about 5,000300,000 standard cubic feetperbarrel of oil charged and therewith stripping hydrorefined oil fromthe catalyst particles; and withdrawing from said hydrorefining zonevaporous effiuent and recovering therefrom a hydrorefined product ofimproved purity.

Many types. of heavy hydrocarbon oils may be treated by means of thisinvention including full boiling range crude oil, topped or reducedcrude oil, atmospheric distillates, heavy cycle oils from thermally orcatalytically cracked stock, light and heavy'vacuum gas oils, etc. Theinstant process is particularly well adapted to hydrorefiningstoc'kscontaining oil-insoluble asphaltenes such as crude oil and cruderesidua; ,of these, crude oil is a preferred .stock because thesoil-insoluble asphaltenes being in their native environment arecolloidally dispersed and thus more readily converted to oil-solublehydrocarbons, whereas the asphaltenes in reduced crude have already beenagglomerated to some extent by reason of a the reboil temperature offractionationand are therefore less easily converted. Another obviousadvantage in hydrotreating :crude oil ,in toto, rather than fractionsthereof, is that subsequent separate treating steps of individual cut'smay be eliminated to a considerable extent. to'upgrading distillatestocks containing oil-soluble resins and maltenes and/ or other of theabove-discussed metallic and non-metallic contaminants, and may beemployed, for example, as the feed preparation unit to a catalytichydrocracking process forthe conversionof cycle oils and gas oils.

As above noted this invention broadly involves con tacting a mixed phaseheavy oil .charge with hydrogen and a pseudo dry particle-formhydrogenation catalyst maintained in a fluidized state under conditionswhich suppress cracking in excess of the extent necessary to convert orremove impurities and which avoid accumulation of a body of liquid phaseoil withinthe hydrorefining zone. Conditions of temperature and pressurewithin the hydrorefining zone are not particularly critical,

should be in excess of about 500 p.s.i.g. with an upper economic limitof about 5000 p.s.i.g., the preferred pressure range beingabout-1000,3000 p.s.i.g. Hydrorefining temperatures willrange from about650 F. to about 950 Higher temperatures are permissible and desir--:able :for lighter charge. stocks such as cycle oil andgas- Theinstantprocess is, however, also well suited oil than for heavier chargestocks. When charging total crude oil, for example, the preferredhydrorefining temperature range is about 650850 F., and in no eventshould the temperature here exceed about 900 F. above which excessivecracking and coke laydown on the catalyst and apparatus internals occur.Under the desired minimal cracking conditions, hydrogenationpredominates over cracking to the extent that the process is slightlyexothermic.

In carrying out this process it is important to minimize cracking, boththermal and catalytic, of the heavy oil charge prior to its introductioninto the hydrorefining zone, while yet imparting suflicient heat theretoto vaporize its lower boiling components and bring the total chargereasonably close to hydrorefining temperature. This is accomplished bypreheating the heavy oil charge, in the absence of catalyst andpreferably in admixture with hydrogen, to a temperature suflicient topartly vaporize it but below the temperature at which substantialthermal cracking thereof can occur. Generally speaking, the chargeshould be preheated to a tempera ture within the range of about 500900F. and preferably in the range of about 650800 F. Thermal crackingwithin the hydrorefining zone proper is substantially avoided byimmersing the point or points of mixed phase oil introduction in ahydrogen atmosphere so that the hot incoming oil is assured of initiallycontacting the catalyst in the presence of hydrogen; such hydrogenatmosphere is preferably provided by introducing a hydrogen-containinggas into the hydrorefining zone below the feed introduction point andflowing both hydrogen and feed cocurrently upwardly through thefluidized catalyst bed.

Maintaining a pseudo-dry fluidized catalyst bed and preventing formationof free liquid phase oil Within the hydrorefining zone are essentialelements of the present process whereby to furnish a high concentrationof active catalyst sites in relation to asphaltene and metal porphyrinmolecules, to avoid flocculation of asphaltenes, and to minimizecracking and coke formation which contribute to rapid catalystdeactivation and loss of liquid product. Such a system is realized bythe conjunctive effect of the following factors: (1) partialvaporization of the feed stock as above described, (2) use of absorptivehydrogenation catalyst particles, (3) employing a relatively lowoilacatalyst Weight ratio, and (4) employing a relatively highhydrogenzoil ratio. A stream of hydrogen-containing gas, which in acommercial process may contain up to 50% of vapors other than hydrogenis passed upwardly through the catalyst bed at a rate within the rangeof from about 5,000 to about 300,000 standard cubic feet of hydrogen perbarrel of total oil charged, and preferably in the range of about10,000- 200,000 standard cubic feet per barrel. This hydrogencontainingstream, herein designated as recycle hydrogen since it is convenientlyrecycled externally of the hydrorefining zone, fulfills a number offunctions; it serves as a hydrogenating agent, a fluidizing medium, aheat carrier and a hydrocarbon stripping medium. In particular, the highrecycle hydrogen rate decreases the partial pressure of the oil vaporand increases vaporization of the oil without raising it to thermalcracking temperature, and maintains the catalyst bed substantiallyisothermal so that no vertical temperature gradient exists. The weighthourly space velocity of the charge, specified here as the weight ratioof total oil charged to catalyst contained in the hydrorefining zone perhour is Within the range of about 0.25-20 pounds of oil per pound ofcatalyst per hour, and preferably in the range of about 1-5 pounds ofoil per pound of catalyst per hour. When the heated mixed phasehydrocarbon charge is initially contacted with absorptive hydrogenationcatalyst particles, the heavier liquid phase portion of the charge ispartly sorbed into the catalyst particles and partly entrained in theupflowing hydrogen stream as fine droplets; the already vaporizedportion of the charge is swept upwardly through the catalyst bed by thehydrogen stream while the lighter liquid phase portion of the charge isvaporized by contact with hot catalyst particles and hydrogen. By virtueof the combined efifects of vaporization, gas stripping and sorption bycatalyst, no free liquid phase oil can form within the hydrorefiningzone. The non-volatilized oil is sorbed into the catalyst particleswhich, however, remain dry and free flowing. This heavy fraction, whichis rich in impurities, is thus exposed to a large number of activecatalyst sites and is subjected to mild cracking and hydrogenation underthe most favorable conditions to yield lower-boiling hydrocarbons ofsubstantially reduced impurity content. The upflowing hydrogen streamstrips off from the catalyst particles the lower-boiling hydrorefinedoil as it is formed.

The efiluent from the hydrorefining zone is passed through an upperparticle separation zone and is withdrawn from the upper portion thereofas a substantially catalyst-free, vaporous stream comprising hydrogen,light hydrocarbon gases, oil vapors, and which may contain someentrained liquid droplets. Hydrorefined oil is recovered from thisoverhead stream, while the hydrogen separated therefrom is returned tothe hydrorefining zone together with outside hydrogen to replenish thenet hydrogen consumption which may range from 200-2000 standard cubicfeet per barrel of charge depending upon the nature of the charge.

The pseudo-dry catalyst system is especially advantageous where theheavy oil charge contains oil-insoluble asphaltenes, which are veryeffectively converted by the autosolvent hydrorefining mechanisminhering in this process. As previously pointed out, asphaltenes whichhave been hydrorefined under mild hydrogenative cracking conditions toyield oil-soluble high-boiling hydrocarbons comprise an excellentsolvent for untreated asphaltenes which are themselves pentane-iusolubleand are colloidally dispersed in a crude oil charge. Through propercorrelation of weight hourly space velocity and recycle hydrogen rate,not all of the hydrorefined oil is removed from the catalyst particlesby hydrogen stripping, but a portion of the hydrorefined asphaltenes,which are among the highest boiling components of the hydrorefining zoneefliuent, is left sorbed in the catalyst particles to act as a solventfor incoming asphaltenes and reaches an equilibrium level in a lined-outoperation. The heavier liquid phase portion of the raw charge, rich inasphaltenes, is sorbed into the catalyst particles and the asphaltenesare then dissolved in the particle-held solvent thereby acceleratingtheir conversion via selective hydrocracking to additional asphaltenesolvent. Part vof the solvent is stripped from the particles by thehydrogen stream, but the remainder of the solvent is left sorbed thereinto dissolve additional incoming asphaltenes. The untreated asphaltenescontained in the heavy oil charge therefore constitute a continuoussource of asphaltene solvent by autogeneration in situ and preferentialretention thereof by the absorptive hydrogenation catalyst particles.

Non-metallic impurities such as nitrogen, sulfur and oxygen areconverted by the present process to ammonia, hydrogen sulfide and waterrespectively, which are removed from the hydrorefining zone togetherwith the mixed-phase efiluent stream. Metallic impurities such asnickel, iron and vanadium are deposited upon the catalyst and graduallybuild up in concentration; although catalyst activity is notparticularly impaired thereby under the condition utilized herein, itmay be desirable to withdraw, continuously or intermittently, asmall'slipstream of catalyst from the hydrorefining zone, to chemicallyregenerate it by any suitable means such as treating with hydrogenchloride and/ or chlorine 'to volatilize the metals, and to return theregenerated catalyst of reduced metal content to the hydrorefining zone.

The hydrogenation catalyst of the present invention can be broadlycharacterized as comprising a metallic component having hydrogenationactivity composited with a refractory inorganic oxide carrier ofsynthetic or natural origin havinga medium-to-high surface area and awelldeveloped pore structure asis familiar to those skilled in the artof-hydrocarbon catalysis; The composition and method of manufacturingthecatalyst is not important to the present invention save only that ithave the necessary absorbency to retain substantial .amounts of liquidphase material within its pores in order to operate as a pseudodrysystem. Suitable metallic components having hydrogenation activity arethe metals ofGroups VB, VIB, and VIII ofthe Periodic Table, e.g.,vanadium, niobium, tantalum, molybdenum, tungsten, chromium, iron,cobalt, nickel, platinum, palladium, iridium, osmium rhodium, ruthenium,and compounds thereof. The hydrogenation catalyst may comprise any oneor combination of any number of such metals which may exist in theelemental state or as the oxides or sulfides thereof in varying degreesof oxidation. The catalytic concentration of the metallic component orcomponents, stated here on the basis of the elemental metal, will dependprimarily on the particularv metal involved; for example, the Group VImetals are preferably present in an amount within the range of about1-20%' by weight, the iron group metals in an amount within the range ofabout 02-10%, and the platinum group metals in an amount within therange of about 0.014%. Suitable refractory inorganic oxide carriersinclude alumina, silica, Zirconia, magnesia,.titania, thoria, boria,strontia, hafnia and mixtures of two or more oxides such assilicaalumina, silica-zirconia, silica-magnesia, silica-titania,alumina-zirconia, alumina-magnesia, aluminatitania, magnesia-zirconia,titania-Zirconia, magnesia-titania, silica-alumina-zirconia,silica-alumina-magnesia, silica-alumina-titania, silica-magnesiazirconia, silica-magnesia-titania, etc. The carrier maycompriseadditional promoters such as combined halogens, particularlyfluorine or chlorine, boric acid, phosphoric acid and boron phosphate.The carrier may be formed by any of numerous techniques known to thoseskilled in the art such as acid-treating a natural clay,.coprecipitationor successive precipitation from hydrosols, frequently coupled with oneor. more activating steps including hot oil aging,,steaming drying,oxidizing,.reducing, calcining,'etc. The pore structure of the carrier,commonly defined in terms of surfacelarea, pore diameter and'porevolume, maybe developed to within specified limits, for example, byaging the hydrosol and/ or hydrogel under. controlled acidic and/ orbasic conditions at ambient or elevated temperature, by gelling thecarrierat a critical pH, or by treating the carrier with variousinorganic or organic reagents. The catalytically active metalliccomponent or components may be composited. withthe carrier by.impregnating the freshly precipitated or finished carrier with asolution of a soluble metal compound or by coprecipitating the metalwith the carrier from an aqueous solution thereof. A hydrogena 'tioncatalyst appropriate for use in the present-invention will have asurface area of'about 50-700 square meters per gram, a pore diameter ofabout 20-300 A, a pore volume of about 0.10-0.80milliliter per gram, andan apparent bulk density of about.0'.200.80 gram per cubic centimeter.Measurement ofsurface area, pore diameter and porevolume of catalyticcomposites may be done ac- I cording to the methods set forth inCatalysis, volume I, pp. 37-40,,Reinhold PublishingCornpany (1954). The

catalyst particles themselves preferably should have diameters rangingfrom about 5 to about 1000 microns in order,

to functionproperly in a fluidized bed; in the case of nonsphericalparticles the maximum dimension of such particle should fall' withinthis range- Particle sizes-of this magnitude may be readily achieved byspray-drying the carrier or by grinding the catalyst in a colloid mill.By way of specific example, a very satisfactory hydrogenation catalystcomprises 2% nickel and 16% molybdenum on an equimolar alumina-silicacarrier (63 Al O /37% SiO another good catalyst comprises 1% nickel and8% molybdenum on an alumina-silica-boron phosphate carrier generalpreparation of which is described in US. Patent The present process maybe further illustrated upon reference to the accompanying drawing whichis a simplilied flow diagram embodying the principalfeatures of theinvention insofar as they are capable of graphical representation. Heavyoil charge. is introduced through line 1, mixed with hydrogen from line19, and passedthrough combined feed preheater 2 wherein about 50-75% ofthe hydrocarbonaceous charge is vaporized. The heated mixed phase feedis passed via transfer line 3 and toroidal feed distributor, .6 into thelower portion of vertical reactor-.4 which contains a fluidized catalystbed 5. Heated stripping and fiuidizing hydrogen is fed'to the bottom ofreactor 4- from hydrogen preheater 17 through transfer line 18. The-hydrogen is distributed through perforated plate 7 and flows upwardlyaround feed distributor 6 into catalyst bed 5 wherein the sorbed oil ishydrorefined and stripped from the catalyst particles. The upper portionof the reaction vessel comprises a particle separation zone 8 ofenlarged cross-sectional areawherein the-catalyst is disengaged from themixed phase reactor efiluent. A

off through line'19 and admixed with the heavy oil chargev to suppresscoking in heater 2. This proportion may range from 20% to of the totalrecycle hydrogen flow. It'is preferred, however, that a major proportionof the hydrogen be separately preheated in heater 17 and charged to thehydrorefining zone through line 18; in some cases, this strippinghydrogen may be heated to as much as F. above the temperature. of thecombined feed inline 3, since it serves to raise the feed from preheattemperature to hydrorefining temperature which is best done in thesimultaneous presence of hydrogenand catalyst to minimize thermalcracking. The stripping hydrogen is preferably heated to within therange: of about 600-1000 F.

' Various additions to and modifications of this flow scheme will beobvious to those skilled inthe art. For example, a catalyst regeneratorvessel may be connected with reactor 4 such that a dragstream ofcatalyst is continuously or intermittantly regenerated by metal and cokeremoving techniques. The unit may be operated in conjunction withhydrogen production or purification facilities whereby a stream ofhydrogen iscontinuously withdrawn from the. recycle system to maintainhydrogen purity ata constant level, and make-up hydrogen may be added toline 1 instead of line ,12. The hot overhead vapors in line 9 may beheat exchanged against heavy oil charge or recycle hydrogen prior. tobeing cooled in con.-

' denser 10. A pipe grid may be substituted for perforated plate 7.Cyclone separators, electricalprecipitators or other separationequipment may be used in lieu of, or incon uncti-on with, the enlargedarea particle separation.

. EXAMPLE 'I A Wyoming sour crude oil is hydrorefined by theabovedescribed continuous process in the presence of a pseudodrycatalyst comprising 2% nickel and 16% molybdenum on a porous refractorysupport consisting of 68% The charge 1 Al O SiO 22% BPO and having aparticle size in the range of 10-150 microns. The Wyoming sour crude oilhas a gravity of 22.5 API and contains 2.8% by weight of sulfur, 2700p.p.m. of nitrogen, and 80 p.p.m. of vanadium and p.p.m. of nickel asmetallo-organic complexes; in addition, this sour crude comprises 8.3%by weight of pentane-insoluble asphaltenes. The crude oil is admixedwith recycle hydrogen of 90% hydrogen purity in the ratio of 17,000standard cubic feet per barrel of total oil charged, the mixture ispreheated to 700 F. and charged to the hydrorefining zone. The weightratio of total oil charged to catalyst contained in the hydrorefiningzone per hour (WHSV) is 1.5. Stripping and fluidizing hydrogen isseparately preheated to 850 F. and fed to the bottom of thehydrorefining zone in the ratio of 51,000 standard cubic feet perbarrel. The fluid catalyst bed itself is maintained at a temperature of800 F. under a total pressure of 2000 ps.i.g. Net hydrogen consumptionis 1000 standard cubic feet per barrel. Liquid yield on a weight basisis 95 the remaining 5% of the charge is converted to light gases asfollows: 2% to C -C hydrocarbons, 1.9% to H S, 1.1% to H O. A comparisonof the gravities and impurities levels of the total crude charge andliquid product is given in Table I.

Table I Liquid Product EXAMPLE II A topped Wyoming sour crude oil (90%of material boiling below 400 F. removed) is hydrorefined by theabove-described continuous process in the presence of a pseudo-drycatalyst comprising 2% nickel and 16% molybdenum on a porous refractorysupport consisting of 63% alumina-37% silica and having a particle sizein the range of 10-150 microns. The topped crude oil has a gravity of19.5 API and contains 3% by weight of sulfur, 2850 p.p.m. of nitrogen,and 84 p.p.m. of vanadium and 21 p.p.m. of nickel as metallo-organiccomplexes; in addition, this topped crude comprises 8.5% by weight ofpentane-insoluble asphaltenes. The topped crude oil is admixed withrecycle hydrogen of 90% hydrogen purity in the ratio of 14,000 standardcubic feet per barrel of total oil charged, the mixture is preheated to725 F. and charged to the hydrorefining zone. The weight hourly spacevelocity (WHSV) is 0.85. Stripping and fiuidizing hydrogen is separatelypreheated to 820 F. and fed to the bottom of the hydrorefining zone inthe ratio of 42,000 standard cubic feet per barrel. The fluid catalystbed itself is maintained at a temperature of 775 F. under a totalpressure of 2000 p.s.i.g. Net hydrogen consumption is 1070 standardcubic feet per barrel. Liquid yield on a weight basis is 95% theremaining 5% of the charge is converted to light gases as follows: 2% toC -C hydrocarbons, 2% to H S and 1% to H O. A comparison of thegravities and impurities levels of the topped crude charge and liquidproduct is given in Table II:

Table II Topped Crude Charge Liquid Product It will be observed from thedata given in Examples I and II that vanadium removal exceeds 99.9%,nickel removal exceeds 99.8%, and conversion of pentane-insolubleasphaltenes is in excess of 99.6%. The 31 API product recovery is byweight, which for a 22.5 API charge corresponds to a liquid volume yieldof about 102%. Selective conversion of asphaltenes and metalloorganiccomplexes with minimum overall cracking is quite apparent in view of thehigh weight recovery and gravity reduction.

These beneficial results are obtained through the use of a pseudo-dryfluidized bed of absorptive catalyst particles obtained by partial feedvaporization, a high catalyst: feed ratio, and a high hydrogentfeedratio. With respect to asphaltene conversion by autosolventhydrorefining, the liquid phase converted asphaltenes sorbed in thecatalyst particles act as an asphaltene solvent for incoming asphalteneswhich upon conversion provide a continuous source of additional solvent.i

I claim as my invention:

1. A process for hydrorefining a heavy hydrocarbon oil containingasphaltenes which comprises maintaining in a hydrorefining zone underhydrorefining conditions a pseudo-dry fluidized bed of absorptivehydrogenation catalyst particles, partially vaporizing said heavy oil bypreheating it in the absence of catalyst to a temperature below that atwhich any substantial thermal cracking thereof can occur, introducingthe partially vaporized oil into said hydrorefining zone and contactingit in the presence of hydrogen with said catalyst particles atasphaltenehydrorefini'ng conditions, sorbing unvaporized oil comprisinghydrorefined asphaltenes into said catalyst particles to avoid anysubstantial accumulation of free liquid phase oil within thehydrorefining zone, flowing a hydrogen-containing gas upwardly throughsaid hydrorefining zone and therewith stripping hydrorefined oil fromthe catalyst particles, withdrawing from said hydrorefining zonevaporous efiluent and recovering therefrom a hydrorefining product ofimproved purity.

2. The process of claim 1 further characterized in that said heavyhydrocarbon oil is a crude oil.

3. The process of claim 1 further characterized in that said heavyhydrocarbon oil is a vacuum gas oil.

4. The process of claim 1 further characterized in that said heavyhydrocarbon oil is a heavy cycle oil.

5. The process of claim 1 further characterized in that said heavy oilis preheated in admixture with hydrogen.

6. The process of claim 1 further characterized in that said heavy oilis preheated to a temperature in the range of about 500-900 F.

7. The process of claim 1 further characterized in that saidhydrorefining zone is maintained at a temperature in the range of about650950 F. and a pressure in excess of about 500 p.s.i.g.

8. The process of claim 1 further characterized in that a majorproportion of said hydrogen-containing gas is preheated separately fromthe heavy oil charge to a temperature in the range of about 600-1000 F.prior to its introduction into said hydrorefining zone.

9. A process for hydrorefining a heavy hydrocarbon oil containingasphaltenes which comprises maintaining in a hydrorefining zone, at atemperature in the range of about 650950 F. and a pressure in the rangeof about 500-5000 p.s.i.g., a pseudo-dry fluidized bed of absorptivehydrogenation catalyst particles; partially vaporizing said heavy oil bypreheating it in the absence of catalyst to la temperature in the rangeof about 500900 F. but below that temperature at which any substantialthermal cracking thereof can occur; charging the partially vaporized oilinto said hydrorefining zone at a rate of about 0.25-20 pounds of totaloil charged per pound of catalyst present in said zone per hour, andtherein contacting said partially vaporized oil in the presence ofhydrogen with said catalyst particles at asphaltene-hydrorefining 11conditions; sorbing unvaporized oil comprising hydrorefined asphaltenesinto said catalyst particles to avoid any substantial accumulation offree liquid phase oil within the hydrorefining zone; flowing a heatedhydrogen-containing gas upwardly through said hydrorefining zone at arate of about 5,000-300,000 standard cubic feet per barrelof oil chargedand therewith stripping hydrorefined oil from the catalyst particles;and with drawing from said hydrorefining zone vaporous effluent andrecovering therefrom a hydrorefined product of improved purity. V

10. A process for hydrorefining a heavy hydrocarbon oil containingasphaltenes which comprises,.the steps of 2 (1) partially vaporizing theoil by. preheating it to a temperature below that at which anysubstantial thermal cracking thereof can occur;

(2) maintaining in a hydrorefining zone under hydrorefining conditionsa':pseudo-dry fluidized bed of absorptive hydrogenation catalystparticlesv having sorbed therein a liquid-phase asphaltene solventcomprising hydrorefined asphaltenes;

(3) introducing said partially vaporized oil into said hydrorefiningzone and contacting it in the presence of hydrogen with saidsolvent-bearing catalyst particles at asphaltene-hydrorefiningconditions;

(4) sorbing unvaporized oil comprising hydrorefined 12 asphaltenes intosaid solvent-bearing catalyst particles whereby to avoid any substantialaccumulation of free liquid phase oil within the hydrorefining zone, anddissolving in the particle-held solvent the asphaltenes contained in thesorbed oil;

(5) converting said dissolved asphaltenes into additional asphaltenesolvent;

(6) flowing a hydrogen-containing gas upwardly through saidhydrorefining zone and therewith stripping hydrorefined oil from thecatalyst particles but leaving sorbed therein a portion of saidasphaltene solvent;

(7) contacting the resulting stripped solvent-bearing catalyst particleswith additional (incoming heavy oil; and

(8) withdrawing from said hydrorefining zone vaporous eflluent and recovening therefrom hydrorefined. oil of reduced asphaltene content.

References Cited in the file of this patent UNITED STATES PATENTS2,914,463 Nicholson Nova 24, 1959 2,926,132 Weikart et a1. Feb. 23,1960Osborne Feb; 12, 1963'

1. A PROCESS FOR HYDROREFINING HEAVY HYDROCARBON OIL CONTAININGASPHALTENES WHICH COMPRISES MAINTAINING IN A HYDROREFINING ZONE UNDERHYDROREFINING CONDITIONS A PSEUDO-DRY FLUIDIZED BED OF ABSORPTIVEHYDROGENATION CATALYST PARTICLES, PARTIALLY VAPORIZING SAID HEAVY OIL BYPREHEATING IT INTHE ABSENCE OF CATALYST TO A TEMPERATURE BELOW THAT ATWHICH ANY SUBSTANTIAL THERMAL CRACKING THEREOF CAN OCCUR, INTRODUCINGTHE PARTIALLY VAPORIZED OIL INTO SAID HYDROREFINING ZONE AND CONTACTINGIT IN THE PRESENCE OF HYDROGEN WITH SSAID CATALYST PARTICLES ATASPHALTENEHYDROREFINING CONDITIONS, SCORBING UNVAPORIZED OIL COMPRISINGHYDROREFINED ASPHALTENES INTO SAID CATALYST PARTICLES TO AVOID ANYSUBSTANTIAL ACCUMULATION OF FREE LIQUID PHASE OIL WITHIN THEHYDROREFINING ZONE, FLOWING A HYDROGEN-CONTAINING GAS UPWARDLY THROUGHSAID HYDROREFINING ZONE AND THEREWITH STRIPPING HYDROREFINED OIL FROMTHE CATALYST PARTICLES, WITHDRAWING FROM SAID HYDROREFINING ZONEVAPOROUS EFFLUENT AND RECOVERING THEREFROM A HYDROREFINING PRODUCT OFIMPROVED PURITY.